1. Field of the Invention
The present invention relates to the structure of a reflection type liquid crystal display device.
2. Description of the Related Art
A reflection type liquid crystal panel has been known. Also, in an active matrix type liquid crystal panel, there is known a structure in which a peripheral driving circuit is integrated on the same substrate as an active matrix circuit. This structure is known as a peripheral driving circuit integration type.
In a peripheral driving circuit integration type liquid crystal panel, as a result that high picture quality is pursued, a peripheral driving circuit is required to operate at such a high speed as several tens MHz or more.
However, high speed operation causes a problem of heat generation from a device. Especially, since a liquid crystal panel uses a glass substrate or a quartz substrate, the panel has a problem that there is no escape for heat generated by a device (the thermal conductivity of quartz is {fraction (1/100)} or less than that of single crystal silicon).
Also, a reflection type liquid crystal display panel is easy to secure a required aperture factor even if it is miniaturized. Accordingly, it has been considered to use the display panel for a projection type display.
However, since a liquid crystal panel for a projector is miniaturized (about 3 inches or less in diagonal), the above described problem of heat generation (heat generation from a peripheral driving circuit) especially becomes important.
Specifically, the peripheral driving circuit has such problems that the device characteristic is changed or deteriorated, or the device itself is broken by the heat generated by the circuit itself.
An object of the present invention is therefore to provide a structure of a display device capable of solving this sort of problem.
According to one aspect of the present invention, a display device is comprised of a pixel matrix portion; a peripheral driving circuit portion disposed on the same substrate as the pixel matrix portion; a thin film transistor disposed in each of the pixel matrix portion and the peripheral driving circuit portion; an interlayer insulating film made of resin material and disposed over the thin film transistor; and a carbon film disposed on the interlayer insulating film.
According to another aspect of the present invention, a display device is comprised of a pixel matrix portion; a peripheral driving circuit portion disposed on the same substrate as the pixel matrix portion; a thin film transistor disposed in each of the pixel matrix portion and the peripheral driving circuit portion, an interlayer insulating film made of resin material and disposed over the thin film transistor; and a carbon film as a heat releasing layer disposed on the interlayer insulating film.
It is preferable to use a DLC (Diamond-like Carbon) film as the carbon film. The DLC film is a carbon film comprising amorphous carbon having SP3 bonds.